from tkinter import *

def callback():
    print(variable.get())
root = Tk()
root.title("你最喜欢的城市是？")
root.geometry("350x80")
variable = StringVar()
variable.set("北京")
mymenu = OptionMenu(root,variable,"北京","上海","广州","深圳")
mymenu.pack()
Button(root,text = "你的选择是",command = callback).pack()
mainloop()
